have you ever considered a cup hanging infuser basket?
the problem i have found with a tea ball is that the leaves can't unfurl as well. but you should be able to find a tea ball in most stores including discount stores such as walmart or target in the kitchen section

I've also found that tea balls do not properly infuse the tea. Imagine being a robust tea leaf with no room to diffuse your pleasant taste and aroma....you would be an unhappy tea leaf. Infuser baskets are without a doubt the best thing going.

Sears or a grocery store generally have one (get mesh, not one with holes punched in for best results). I buy the biggest I can fit in a mug. The one I have now was meant for use in a teapot, but it works well for a cuppa since there's less tea to take up room inside.

Whittards of Chelsea also sells really nice mugs with infusers, I have one of those too and adore it.

I pack my own tea for work using the filter bags sold by Adagio. They are $3 for 100 ($0.03 each!). I pack them up at home. At work I heat some water, pop in a filter bag already filled with tea, let it steep, toss the bag...done! No cleanup and at such a small price, I don't have any intention of trying something new. The bags are fairly large and have a lot of room for the leaves to unfurl and do their magic.